This invention relates to the fluid sensing art of the type disclosed in U.S. Pat. No. 3,853,006, issued Dec. 10, 1974, and more particularly, to systems for producing fluid level and/or fluid density analogs.
In pressurized storage or other tank systems, it is sometimes difficult or impossible to obtain accurate liquid level indications by the use of conventional devices. In many cases, the absolute tank pressure may be lower or higher than ambient. Many conventional liquid level indicators are influenced by the tank pressure when it is not the same as the ambient. For this reason, they give an erroneous liquid level indication.
In the prior art, relatively unsophisticated densitometers are virtually unknown. However, they are, nevertheless, badly needed. For example, it is important to monitor closely and continuously the density of drilling mud for oil wells or the like.